Programmable resistive materials based on chalcogenide glass are being explored for use as non-volatile memory elements. By applying an external stimulus, such as different voltages of selected polarities to a chalcogenide glass in the presence of an available metal such as silver, the internal structure of the chalcogenide glass can be modified to produce high or low resistance states.
One specific example of a chalcogenide glass being investigated for memory use is germanium-selenide (GexSe100−x). Typically, the chalcogenide glass has an associated layer for supplying a metal, which becomes incorporated with the glass matrix to change resistance states. As examples, the associated layer may be a layer of silver or a layer of silver-selenide (Ag2Se).
While the current focus is on using chalcogenide glass for memory devices, the inventors have discovered another use for chalcogenide glass, namely, as a constant current device.